阅读说明：本技术 基于球壳型超声换能器的3d打印金属件抛光装置及方法 (Spherical shell type ultrasonic transducer-based 3D printing metal part polishing device and method ) 是由 张勤俭 房善想 李海洋 严鲁涛 于 2021-08-24 设计创作，主要内容包括：本发明公开了一种基于球壳型超声换能器的3D打印金属件抛光装置及方法。该装置包括：上基座、工业机器人、球壳型超声换能器、超声电源、下基座和工作池。本发明利用球壳型超声换能器对超声的汇聚作用,将球壳型超声换能器所产生的超声聚焦于待加工的3D打印金属件的表面抛光点上。通过工业机器人来精准控制球壳型超声换能器的运动轨迹,使其凹面贴合待加工3D打印金属件的外形上进行移动。同时,还可以通过控制球壳型超声换能器与待加工3D打印金属件之间的工作距离和调节超声电源的频率以产生不同频率的超声振动,以此来实现对不同3D打印金属件的表面进行处理。(The invention discloses a polishing device and method for a 3D printing metal part based on a spherical shell type ultrasonic transducer. The device includes: the ultrasonic testing device comprises an upper base, an industrial robot, a spherical shell type ultrasonic transducer, an ultrasonic power supply, a lower base and a working pool. The invention utilizes the convergence effect of the spherical shell type ultrasonic transducer on the ultrasound to focus the ultrasound generated by the spherical shell type ultrasonic transducer on the surface polishing point of the 3D printing metal piece to be processed. The movement track of the spherical shell type ultrasonic transducer is accurately controlled through the industrial robot, and the concave surface of the spherical shell type ultrasonic transducer is attached to the appearance of a 3D printing metal piece to be processed to move. Meanwhile, the surface of different 3D printing metal pieces can be treated by controlling the working distance between the spherical shell type ultrasonic transducer and the 3D printing metal piece to be processed and adjusting the frequency of the ultrasonic power supply to generate ultrasonic vibration with different frequencies.)

1. The utility model provides a 3D prints metalwork burnishing device based on spherical shell type ultrasonic transducer which characterized in that includes: the ultrasonic testing device comprises an upper base, an industrial robot, a spherical shell type ultrasonic transducer, an ultrasonic power supply, a lower base and a working pool; the industrial robot is arranged on the upper base, the tail end of the industrial robot is connected with a spherical shell type ultrasonic transducer, and the industrial robot is used for controlling the movement of the spherical shell type ultrasonic transducer; the ultrasonic power supply is connected with the spherical shell type ultrasonic transducer and is used for exciting the spherical shell type ultrasonic transducer to generate a high-frequency electric signal of ultrasonic vibration; the working pool is arranged on the lower base and contains polishing liquid and a 3D printing metal piece to be processed; the spherical shell type ultrasonic transducer is soaked in the polishing solution, energy generated by ultrasonic vibration is focused on the surface of the 3D printing metal piece to be processed through the polishing solution, and surface polishing treatment of the 3D printing metal piece to be processed is completed.

2. The polishing device for the 3D printed metal piece based on the spherical shell type ultrasonic transducer is characterized in that a clamp is arranged in the working pool and used for clamping the 3D printed metal piece to be processed.

3. The spherical shell type ultrasonic transducer based 3D printing metal piece polishing device as claimed in claim 2, wherein the clamp is detachable.

4. The spherical shell type ultrasonic transducer based 3D printing metal piece polishing device according to claim 1, further comprising: and the robot controller is connected with the industrial robot and is used for controlling the moving track of the industrial robot.

5. The spherical shell type ultrasonic transducer based 3D printing metal piece polishing device according to claim 4, further comprising: and the system control cabinet is connected with the robot controller, is used for carrying out analysis operation on the kinematics and dynamics of the industrial robot, is communicated with the robot controller, and realizes the control on the moving track of the spherical shell type ultrasonic transducer.

6. The polishing device for the 3D printed metal piece based on the spherical shell type ultrasonic transducer is characterized in that the frequency range of the ultrasonic power supply is 10 KHz-40 KHz.

7. A polishing method for a 3D printed metal part based on a spherical shell type ultrasonic transducer is characterized in that the method is applied to the polishing device for the 3D printed metal part based on the spherical shell type ultrasonic transducer of any one of claims 1 to 6, and the method comprises the following steps:

acquiring a three-dimensional model diagram of a 3D printed metal piece to be processed;

determining a polishing path according to the three-dimensional model map;

converting the polishing path into three-dimensional space coordinates;

performing analytical operation on the kinematics and dynamics of the industrial robot to obtain each joint corner of the industrial robot;

obtaining the terminal pose coordinates of the industrial robot according to the joint corners;

and adjusting the end pose of the industrial robot according to the three-dimensional space coordinates and the end pose coordinates of the industrial robot.

Technical Field

The invention relates to the technical field of fine part polishing, in particular to a polishing device and method for a 3D printing metal part based on a spherical shell type ultrasonic transducer.

Background

The appearance complexity of the metal product is further improved due to the appearance of the 3D metal printing technology, the metal product has the advantages that the complex metal component can be printed in a short time, but the surface of the metal component after printing and forming is provided with a plurality of floating powder, even though sand blasting is carried out, the surface is still rough and does not meet the actual product appearance requirement, and therefore the surface of the 3D printed metal part needs to be polished after sand blasting is completed. The metal part formed by 3D printing has a complex structure, and the surface of the metal part cannot be polished by using the traditional polishing technology.

The main surface polishing methods for metal components at present comprise: (1) mechanical polishing, (2) chemical polishing, (3) electrochemical polishing (electropolishing). Mechanical polishing usually adopts a grinding head to polish, and a workpiece is directly subjected to friction polishing with a polishing wheel through rotation and swinging. However, after polishing, a hardened layer exists on the surface of the workpiece, the surface of the component is not smooth, and for metal components with complex shapes, the surface of the component is difficult to polish by a mechanical polishing method. The chemical polishing can perform surface polishing treatment on metal components with complicated shapes, but the polishing solution for chemical polishing has complicated components, high cost and great harm to human bodies and the environment, so the chemical polishing is not suitable for 3D printing metal parts. Electrochemical polishing, also called electropolishing, can accomplish the polishing treatment of metal members with complex external structures, but the surface quality of electrochemical polishing of metal members of different materials is different. The electrochemical polishing can dissolve the convex points and concave points on the surface of the metal piece, which can affect the integrity of the workpiece, especially the small workpieces and can hardly ensure the accuracy of the size and the geometric shape of the workpiece. The 3D printing metal part has higher requirements on the size precision of parts, the printed part structure is often very complex, and the design requirements of workpieces can be influenced by adopting electrochemical polishing. In addition, it is difficult to achieve high polishing quality on rough machined parts using electrochemical polishing.

Traditional mechanical polishing can not carry out polishing treatment on complex metal components, and chemical polishing and electrolytic polishing have high efficiency, but have high cost, are harmful to the environment and the health of human bodies, and are not suitable for 3D printed metal parts with complex shapes and high integrity of workpieces.

Disclosure of Invention

The invention aims to provide a polishing device and a polishing method for a 3D printing metal part based on a spherical shell type ultrasonic transducer, which are used for polishing the surface of the 3D printing metal part by using a fluid vibration polishing method.

In order to achieve the purpose, the invention provides the following scheme:

a polishing device for a 3D printing metal part based on a spherical shell type ultrasonic transducer comprises: the ultrasonic testing device comprises an upper base, an industrial robot, a spherical shell type ultrasonic transducer, an ultrasonic power supply, a lower base and a working pool; the industrial robot is arranged on the upper base, the tail end of the industrial robot is connected with a spherical shell type ultrasonic transducer, and the industrial robot is used for controlling the movement of the spherical shell type ultrasonic transducer; the ultrasonic power supply is connected with the spherical shell type ultrasonic transducer and is used for exciting the spherical shell type ultrasonic transducer to generate a high-frequency electric signal of ultrasonic vibration; the working pool is arranged on the lower base and contains polishing liquid and a 3D printing metal piece to be processed; the spherical shell type ultrasonic transducer is soaked in the polishing solution, energy generated by ultrasonic vibration is focused on the surface of the 3D printing metal piece to be processed through the polishing solution, and surface polishing treatment of the 3D printing metal piece to be processed is completed.

Optionally, a clamp is arranged in the working pool and used for clamping the 3D printing metal piece to be processed.

Optionally, the clamp is detachable.

Optionally, the method further comprises: and the robot controller is connected with the industrial robot and is used for controlling the moving track of the industrial robot.

Optionally, the method further comprises: and the system control cabinet is connected with the robot controller, is used for carrying out analysis operation on the kinematics and dynamics of the industrial robot, is communicated with the robot controller, and realizes the control on the moving track of the spherical shell type ultrasonic transducer.

Optionally, the frequency range of the ultrasonic power source is 10KHz to 40 KHz.

The invention also provides a polishing method of the 3D printed metal part based on the spherical shell type ultrasonic transducer, which is applied to the polishing device of the 3D printed metal part based on the spherical shell type ultrasonic transducer, and the method comprises the following steps:

acquiring a three-dimensional model diagram of a 3D printed metal piece to be processed;

determining a polishing path according to the three-dimensional model map;

converting the polishing path into three-dimensional space coordinates;

performing analytical operation on the kinematics and dynamics of the industrial robot to obtain each joint corner of the industrial robot;

obtaining the terminal pose coordinates of the industrial robot according to the joint corners;

and adjusting the end pose of the industrial robot according to the three-dimensional space coordinates and the end pose coordinates of the industrial robot.

According to the specific embodiment provided by the invention, the invention discloses the following technical effects:

the invention utilizes the convergence effect of the spherical shell type ultrasonic transducer on the ultrasound to focus the ultrasound generated by the spherical shell type ultrasonic transducer on the surface polishing point of the 3D printing metal piece to be processed. The movement track of the spherical shell type ultrasonic transducer is accurately controlled through the industrial robot, and the concave surface of the spherical shell type ultrasonic transducer is attached to the appearance of a 3D printing metal piece to be processed to move. Meanwhile, the surface of different 3D printing metal pieces can be treated by controlling the working distance between the spherical shell type ultrasonic transducer and the 3D printing metal piece to be processed and adjusting the frequency of the ultrasonic power supply to generate ultrasonic vibration with different frequencies.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings needed to be used in the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings without inventive exercise.

Fig. 1 is a schematic structural diagram of a 3D printing metal part polishing device based on a spherical shell type ultrasonic transducer according to an embodiment of the present invention;

fig. 2 is a schematic structural diagram of a spherical shell type ultrasonic transducer according to an embodiment of the present invention; wherein, (a) is a front view, (b) is a left view, (c) is a top view, and (d) is a principle diagram of the sound gathering energy shell;

fig. 3 is a flowchart of the operation of the 3D printing metal part polishing apparatus based on the spherical shell type ultrasonic transducer according to the embodiment of the present invention.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

The invention aims to provide a polishing device and a polishing method for a 3D printing metal part based on a spherical shell type ultrasonic transducer, which are used for polishing the surface of the 3D printing metal part by using a fluid vibration polishing method.

In order to make the aforementioned objects, features and advantages of the present invention comprehensible, embodiments accompanied with figures are described in further detail below.

As shown in fig. 1, the 3D printing metal piece polishing apparatus based on spherical shell type ultrasonic transducer provided by the present invention includes: the ultrasonic testing device comprises an upper base 1, an industrial robot 2, a spherical shell type ultrasonic transducer 3, an ultrasonic power supply 5, a lower base 6 and a working pool 7.

The working pool 7 is arranged on the lower base 6, a clamp is arranged in the working pool 7, and the clamp is used for clamping the 3D printing metal piece 4 to be processed. The anchor clamps are detachable construction, can wait to process the appearance of 3D printing metalwork 4 according to the difference, change suitable anchor clamps, accomplish the centre gripping. The to-be-processed 3D printing metal piece 4 is fixed inside the working pool 7 through a clamp, so that the to-be-processed 3D printing metal piece 4 is completely soaked in the polishing solution 10.

The spherical shell type ultrasonic transducer 3 is mounted on a flange at the end of the industrial robot 2. The industrial robot 2 is mounted on an upper base 1. The spherical shell type ultrasonic transducer 3 performs surface polishing treatment on the to-be-processed 3D printed metal part 4 which is completely soaked in the working pool 7 of the polishing solution 10 according to a planned path along with the industrial robot 2.

The ultrasonic power supply 5 is connected with the spherical shell type ultrasonic transducer 3, the ultrasonic power supply 5 is used for providing an electric signal of ultrasonic vibration, the ultrasonic power supply has a frequency adjusting function, the frequency adjustable range is 10 KHz-40 KHz, and the frequency of the ultrasonic power supply 5 can be adjusted to required parameters according to different processing requirements of the 3D printing metal piece 4 to be processed.

The spherical shell type ultrasonic transducer 3 converts an electric signal of an ultrasonic power supply 5 into mechanical vibration with ultrasonic frequency, the generated mechanical vibration is transmitted through the polishing solution 10, energy generated by the ultrasonic vibration is focused on the to-be-processed 3D printed metal part 4, the industrial robot 2 controls the motion track of the spherical shell type ultrasonic transducer 3, and the complex surface of the to-be-processed 3D printed metal part 4 is polished.

The structure of the spherical shell type ultrasonic transducer 3 is shown in fig. 2(a) - (c), the principle is shown in fig. 2(D), under the action of ultrasound, the spherical shell type ultrasonic transducer 3 converges the energy in the sound field to a point, F represents the distance from the spherical shell type ultrasonic transducer 3 to the polished surface of the 3D printing metal part 4 to be processed, F represents the polished point, and the distance changes along with the movement of the industrial robot 2.

The above-mentioned device still includes: and the robot controller 8 is used for realizing the motion trail control of the industrial robot 2 and strengthening the surface of the to-be-processed 3D printed metal part 4 of the spherical shell type ultrasonic transducer 3 according to a planned path. The robot controller 8 is also used for controlling the working distance between the spherical shell type ultrasonic transducer 3 and the 3D printing metal piece 4 to be processed.

The above-mentioned device still includes: and the system control cabinet 8 is used for performing analysis operation on kinematics and dynamics of the industrial robot 2, communicating with the robot controller 9 and controlling the moving track of the spherical shell type ultrasonic transducer 3.

Based on the device, the invention also provides a polishing method of the 3D printing metal part based on the spherical shell type ultrasonic transducer, which comprises the following steps:

step 101: and acquiring a three-dimensional model diagram of the 3D printed metal piece to be processed.

Step 102: and determining a polishing path according to the three-dimensional model map.

Step 103: and converting the polishing path into three-dimensional space coordinates.

Step 104: and carrying out analytic operation on the kinematics and dynamics of the industrial robot to obtain each joint corner of the industrial robot.

Step 105: and obtaining the terminal pose coordinates of the industrial robot according to the joint corners.

Step 106: and adjusting the end pose of the industrial robot according to the three-dimensional space coordinates and the end pose coordinates of the industrial robot.

The specific workflow is shown in fig. 3:

the three-dimensional model diagram of the 3D printing metal part 4 to be processed is led into a system control cabinet 8 by utilizing three-dimensional modeling software SolidWorks, and software Robotsutio in the system control cabinet 8 automatically simulates and controls an industrial robot 2 to generate a path meeting polishing requirements according to the three-dimensional model diagram of the 3D printing metal part 4 to be processed, so that a spherical shell type ultrasonic transducer 3 is driven to carry out an ultrasonic focusing fluid polishing task; then, the software Robotsutio in the system control cabinet 8 converts the motion trail of the industrial robot 2 generated by simulation into three-dimensional space coordinate data and transmits the three-dimensional space coordinate data to the robot controller 9; the robot controller 9 processes the transmitted three-dimensional space coordinate data, and meanwhile, in order to improve the polishing precision, the kinematics analysis operation needs to be performed on the industrial robot 2, and each joint corner of the industrial robot 2 corresponding to the spherical shell type ultrasonic transducer 3 on the motion track is calculated; when the dynamics of the robot is analyzed and calculated, modeling calculation is respectively carried out on the kinematics of the mechanical arm of the industrial robot 2 by adopting a D-H parameter representation method to obtain each joint corner of the robot.

TABLE 1 Flexible arm kinematics D-H parameters

q_i(rad)、a_i(mm)、d_i(mm)、α_i(rad) indicates joint angle, link length, link offset and link torsion angle, respectively. According to the D-H parameters, the Cartesian space coordinate system is subjected to rotation and translation transformation, and then the coordinate systems of two adjacent joint connecting rods can be expressed as follows:

and the general homogeneous transformation matrix can be obtained by expanding the matrix:

the transformation matrix of each joint can be obtained according to the derivation process, different joint rotation angle formulas of the industrial robot 2 can be obtained by multiplying the 6 joints, the calculated data are three-dimensional coordinate data and are stored in the robot controller 9, and the robot controller 9 integrates the data to generate a new motion track for controlling the industrial robot 2; the robot controller 9 establishes communication with the industrial robot 2, and after the ultrasonic power supply 5 is started, the ultrasonic frequency is determined according to different use requirements of different parts and different reference values of surface roughness; if the surface roughness of the part is larger, the required ultrasonic frequency is higher, the spherical shell type ultrasonic transducer 3 moves according to a path planned by the industrial robot, and the surface polishing treatment is carried out on the 3D printing metal part 4 to be processed; the robot controller 9 adjusts the pose according to the polishing path of the industrial robot 2; adjusting the terminal pose of the industrial robot 2 according to the dynamic operation process of the industrial robot 2, and processing the data to obtain a homogeneous transformation matrix of each joint:

and (4) sorting and multiplying the formulas to obtain the three-dimensional space coordinate data of the terminal pose of the robot. The robot controller 9 can adjust the end pose of the industrial robot 2 according to the data, so that the acoustic focusing point of the spherical shell type ultrasonic transducer 3 is always on the surface of the 3D printing metal part 4 to be processed, the axis is always in the normal direction of the processed surface, and the processing quality is uniform and consistent.

When the surface polishing treatment is carried out on the 3D printing metal part 4 to be processed, the spherical shell type ultrasonic transducer 3 carries out the surface polishing on the 3D printing metal part 4 to be processed along the planned motion path from the initial test position of the system to the starting point of the planned motion path through the motion control of the industrial robot 2. After the surface polishing of the single pass is finished, the surface roughness of the 3D printing metal part 4 is measured, and whether the ultrasonic focusing fluid polishing of the next pass is carried out or not is determined according to the use requirements of different parts and different reference values of the surface roughness. And if necessary, returning to the starting point of the path again, and performing the next surface polishing treatment. When the surface roughness of the 3D printing metal part 4 meets the use requirement, all the work of the surface polishing treatment of the 3D printing metal part 4 to be processed is finished, and the industrial robot 2 returns to the initial position of the system.

The invention utilizes the convergence effect of the spherical shell type ultrasonic transducer on the ultrasound to focus the ultrasound generated by the spherical shell type ultrasonic transducer on the surface polishing point of the 3D printing metal piece to be processed. The movement track of the spherical shell type ultrasonic transducer is accurately controlled through the industrial robot, and the concave surface of the spherical shell type ultrasonic transducer is attached to the appearance of a 3D printing metal piece to be processed to move. Meanwhile, the polishing treatment of the surfaces of different 3D printing metal pieces can be realized by controlling the working distance between the spherical shell type ultrasonic transducer and the 3D printing metal piece to be processed and adjusting the frequency of the ultrasonic power supply to generate ultrasonic vibration with different frequencies.

The embodiments in the present description are described in a progressive manner, each embodiment focuses on differences from other embodiments, and the same and similar parts among the embodiments are referred to each other.

The principles and embodiments of the present invention have been described herein using specific examples, which are provided only to help understand the method and the core concept of the present invention; meanwhile, for a person skilled in the art, according to the idea of the present invention, the specific embodiments and the application range may be changed. In view of the above, the present disclosure should not be construed as limiting the invention.